code: def test_scale_factor():
      # Should be same as lat_ts=20 for a sphere
      scale_factor = 0.939692620786
      crs = ccrs.Mercator(
          scale_factor=scale_factor, globe=ccrs.Globe(ellipse="sphere")
      )
      other_args = {
          "ellps=sphere",
          "lon_0=0.0",
          "x_0=0.0",
          "y_0=0.0",
          "units=m",
          f"k_0={scale_factor:.12f}",
      }
      check_proj_params("merc", crs, other_args)
  
      assert_almost_equal(
          crs.boundary.bounds,
          [-18808021, -14585266, 18808021, 17653216],
          decimal=0,
      )
  
file_path: cartopy/lib/cartopy/tests/crs/test_mercator.py
imports: from numpy.testing import assert_almost_equal
  import pytest
  import cartopy.crs
  from .helpers import check_proj_params
label_desc: Use image node_id 7 for calling a global function with example usage: test_scale_factor() without return types